glibc/nptl/pthread_rwlock_rdlock.c
Torvald Riegel cc25c8b4c1 New pthread rwlock that is more scalable.
This replaces the pthread rwlock with a new implementation that uses a
more scalable algorithm (primarily through not using a critical section
anymore to make state changes).  The fast path for rdlock acquisition and
release is now basically a single atomic read-modify write or CAS and a few
branches.  See nptl/pthread_rwlock_common.c for details.

	* nptl/DESIGN-rwlock.txt: Remove.
	* nptl/lowlevelrwlock.sym: Remove.
	* nptl/Makefile: Add new tests.
	* nptl/pthread_rwlock_common.c: New file.  Contains the new rwlock.
	* nptl/pthreadP.h (PTHREAD_RWLOCK_PREFER_READER_P): Remove.
	(PTHREAD_RWLOCK_WRPHASE, PTHREAD_RWLOCK_WRLOCKED,
	PTHREAD_RWLOCK_RWAITING, PTHREAD_RWLOCK_READER_SHIFT,
	PTHREAD_RWLOCK_READER_OVERFLOW, PTHREAD_RWLOCK_WRHANDOVER,
	PTHREAD_RWLOCK_FUTEX_USED): New.
	* nptl/pthread_rwlock_init.c (__pthread_rwlock_init): Adapt to new
	implementation.
	* nptl/pthread_rwlock_rdlock.c (__pthread_rwlock_rdlock_slow): Remove.
	(__pthread_rwlock_rdlock): Adapt.
	* nptl/pthread_rwlock_timedrdlock.c
	(pthread_rwlock_timedrdlock): Adapt.
	* nptl/pthread_rwlock_timedwrlock.c
	(pthread_rwlock_timedwrlock): Adapt.
	* nptl/pthread_rwlock_trywrlock.c (pthread_rwlock_trywrlock): Adapt.
	* nptl/pthread_rwlock_tryrdlock.c (pthread_rwlock_tryrdlock): Adapt.
	* nptl/pthread_rwlock_unlock.c (pthread_rwlock_unlock): Adapt.
	* nptl/pthread_rwlock_wrlock.c (__pthread_rwlock_wrlock_slow): Remove.
	(__pthread_rwlock_wrlock): Adapt.
	* nptl/tst-rwlock10.c: Adapt.
	* nptl/tst-rwlock11.c: Adapt.
	* nptl/tst-rwlock17.c: New file.
	* nptl/tst-rwlock18.c: New file.
	* nptl/tst-rwlock19.c: New file.
	* nptl/tst-rwlock2b.c: New file.
	* nptl/tst-rwlock8.c: Adapt.
	* nptl/tst-rwlock9.c: Adapt.
	* sysdeps/aarch64/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt.
	* sysdeps/arm/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt.
	* sysdeps/hppa/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt.
	* sysdeps/ia64/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt.
	* sysdeps/m68k/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt.
	* sysdeps/microblaze/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt.
	* sysdeps/mips/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt.
	* sysdeps/nios2/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt.
	* sysdeps/s390/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt.
	* sysdeps/sh/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt.
	* sysdeps/sparc/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt.
	* sysdeps/tile/nptl/bits/pthreadtypes.h (pthread_rwlock_t): Adapt.
	* sysdeps/unix/sysv/linux/alpha/bits/pthreadtypes.h
	(pthread_rwlock_t): Adapt.
	* sysdeps/unix/sysv/linux/powerpc/bits/pthreadtypes.h
	(pthread_rwlock_t): Adapt.
	* sysdeps/x86/bits/pthreadtypes.h (pthread_rwlock_t): Adapt.
	* nptl/nptl-printers.py (): Adapt.
	* nptl/nptl_lock_constants.pysym: Adapt.
	* nptl/test-rwlock-printers.py: Adapt.
	* nptl/test-rwlockattr-printers.c: Adapt.
	* nptl/test-rwlockattr-printers.py: Adapt.
2017-01-10 11:50:17 +01:00

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1.2 KiB
C

/* Copyright (C) 2003-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include "pthread_rwlock_common.c"
/* See pthread_rwlock_common.c. */
int
__pthread_rwlock_rdlock (pthread_rwlock_t *rwlock)
{
LIBC_PROBE (rdlock_entry, 1, rwlock);
int result = __pthread_rwlock_rdlock_full (rwlock, NULL);
LIBC_PROBE (rdlock_acquire_read, 1, rwlock);
return result;
}
weak_alias (__pthread_rwlock_rdlock, pthread_rwlock_rdlock)
hidden_def (__pthread_rwlock_rdlock)